1. Field of the Invention
The invention relates generally to devices for mimicking animal sounds, some of these devices being known as turkey calls or elk calls, for example, and to methods of and apparatus for making such animal calls.
2. Discussion of the Prior Art
Conventionally, animal call devices, referred to as animal calls, may be made by craftsmen on a piece by piece basis. The sounds generated by of one animal call may be tuned by the person making the call until the precise sound quality has been achieved. However, in order to provide animal calls on a commercial basis, simple assembly apparatus is desirably used to increase speed of production and allow the manufacture of the animal calls in some quantity. The individual touch provided by the craftsman is less likely to be found in such manufactured animal calls. It may therefore be desirable to improve the manufacturing techniques of animal calls, such as elk calls or turkey calls, and to also improve the resulting product. The type of animal call which as a particular example may be improved by the present invention, is a device consisting of a somewhat "U"-shaped folded frame between which two or even more resilient diaphragms may be stretched to act as reeds. A typically O-shaped aluminum frame may be folded across a diametrical line over onto itself, the folding operation capturing, for example, two resilient diaphragms between the two folded over frame halves. An outer tab on one of the halves may be folded over against the other half of the frame to retain the two frame halves together. Subjecting the frame halves to a linear crimping operation after folding them is intended to increase the retention of typically latex rubber sheets of the diaphragms which function as reeds of such prior art calls. Making calls in a conventional manner as outlined above tends to introduce errors in tensioning the diaphragm to a desired amount of "stretch" across the frame. Even if a certain amount of tension is imparted to the latex rubber sheet, as it is stretched across the frame to be captured by the folding and crimping operations, the rubber latex may tend to slip out from between the two frame halves even after the crimping operation. The crimping operation, though forming the ridge, appears not to establish direct contact by one half of the frame with the other half of the folded over frame.
Another problem that has existed with respect to conventional animal calls, and the manner in which they are being made, relates to a lack in repeatability or consistency in the characteristics of the call devices. Typically latex rubber sheets may be purchased in rolls of latex film sheet material, for example, of a thickness of four thousandth of an inch. The film is manufactured to a width which is typically much wider than desirable. The original rolls of latex film are therefore preferably slit into narrow rolls of approximately two inch in width, for example. The film is then pulled off the roll and stretched across the discussed aluminum frames. A torque or friction drag may be exerted on the shaft of the roll, such that a certain constant tension in the unreeling material might be expected. However, it has been found that the tension at which the material unreels from its storage roll is not constant, a precise tension in the material being not readily ascertainable. It is believed that slitting the rolls to their desired width may cause the material of adjacent layers to adhere to each other with greater or lesser forces of adhesion, requiring a indeterminable amount of force to separate the adjacent layers from each other. Though not readily apparent, the calling sound characteristics of calls appear to be changed by the varying tension in the latex rubber strip as the animal calls are being assembled.
Consequently, a need is seen for improving the manufacturing techniques of animal call devices. It would be particularly desirable to allow the diaphragms or reeds to be stretched across frames of the described shape with a greater degree of precision and with a greater degree of repeatability. It is further desirable to provide a more consistent hold on the diaphragms or reeds of the animal call devices.